diff --git a/sort.go b/sort.go
index c483964..612de2c 100644
--- a/sort.go
+++ b/sort.go
@@ -13,6 +13,7 @@ const (
 	SORT_START_DATE_DESC
 	SORT_FINISH_DATE_ASC
 	SORT_FINISH_DATE_DESC
+	SORT_ERROR
 )
 
 // Sort allows a TimerList to be sorted by certain predefined fields.
@@ -28,8 +29,15 @@ func (timerlist *TimerList) Sort(sortFlag int) error {
 	default:
 		return errors.New("Unrecognized sort option")
 	}
+	timerlist.sortFlag = sortFlag
 	return nil
 }
+func (timerlist *TimerList) refresh() {
+	timerlist.Sort(timerlist.sortFlag)
+	for i, t := range timerlist.timers {
+		t.Id = i
+	}
+}
 
 type timerlistSort struct {
 	timerlists TimerList
@@ -37,15 +45,15 @@ type timerlistSort struct {
 }
 
 func (ts *timerlistSort) Len() int {
-	return len(ts.timerlists)
+	return len(ts.timerlists.timers)
 }
 
 func (ts *timerlistSort) Swap(l, r int) {
-	ts.timerlists[l], ts.timerlists[r] = ts.timerlists[r], ts.timerlists[l]
+	ts.timerlists.timers[l], ts.timerlists.timers[r] = ts.timerlists.timers[r], ts.timerlists.timers[l]
 }
 
 func (ts *timerlistSort) Less(l, r int) bool {
-	return ts.by(ts.timerlists[l], ts.timerlists[r])
+	return ts.by(ts.timerlists.timers[l], ts.timerlists.timers[r])
 }
 
 func (timerlist *TimerList) sortBy(by func(t1, t2 *Timer) bool) *TimerList {
diff --git a/timerlist.go b/timerlist.go
index f4eb09c..ac7c55f 100644
--- a/timerlist.go
+++ b/timerlist.go
@@ -6,32 +6,27 @@ import (
 	"fmt"
 	"io/ioutil"
 	"os"
+	"sort"
 	"strings"
 	"time"
 )
 
 // TimerList represents a list of timer.txt timer entries.
 // It is usually loasded from a whole timer.txt file.
-type TimerList []*Timer
+type TimerList struct {
+	timers   []*Timer
+	sortFlag int
+}
 
 // NewTimerList creates a new empty TimerList.
-func NewTimerList() *TimerList {
-	return &TimerList{}
-}
-
-func (timerlist *TimerList) Size() int {
-	return len([]*Timer(*timerlist))
-}
-
-func (timerlist *TimerList) GetTimerSlice() []*Timer {
-	return []*Timer(*timerlist)
-}
+func NewTimerList() *TimerList                       { return &TimerList{} }
+func (timerlist *TimerList) Size() int               { return len(timerlist.timers) }
+func (timerlist *TimerList) GetTimerSlice() []*Timer { return timerlist.timers }
 
 func (timerlist *TimerList) GetMostRecentTimer() (*Timer, error) {
 	var found *Timer
 	var latest time.Time
-	for i := range *timerlist {
-		t := ([]*Timer(*timerlist))[i]
+	for _, t := range timerlist.timers {
 		if t.FinishDate.IsZero() {
 			if t.StartDate.After(latest) {
 				found = t
@@ -75,11 +70,81 @@ func (timerlist *TimerList) GetTimersWithProject(project string) *TimerList {
 	})
 }
 
+func (timerlist *TimerList) GetContexts() []string {
+	var ret []string
+	added := make(map[string]bool)
+	for _, tmr := range timerlist.timers {
+		for _, c := range tmr.Contexts {
+			if !added[c] {
+				ret = append(ret, c)
+				added[c] = true
+			}
+		}
+	}
+	sort.Strings(ret)
+	return ret
+}
+func (timerlist *TimerList) GetProjects() []string {
+	var ret []string
+	added := make(map[string]bool)
+	for _, tmr := range timerlist.timers {
+		for _, p := range tmr.Projects {
+			if !added[p] {
+				ret = append(ret, p)
+				added[p] = true
+			}
+		}
+	}
+	sort.Strings(ret)
+	return ret
+}
+func (timerlist *TimerList) GetTagKVList() []string {
+	var ret []string
+	added := make(map[string]bool)
+	for _, tmr := range timerlist.timers {
+		for k, v := range tmr.AdditionalTags {
+			tag := fmt.Sprintf("%s:%s", k, v)
+			if !added[tag] {
+				ret = append(ret, tag)
+				added[tag] = true
+			}
+		}
+	}
+	sort.Strings(ret)
+	return ret
+}
+func (timerlist *TimerList) GetTagKeys() []string {
+	var ret []string
+	added := make(map[string]bool)
+	for _, tmr := range timerlist.timers {
+		for k := range tmr.AdditionalTags {
+			if !added[k] {
+				ret = append(ret, k)
+				added[k] = true
+			}
+		}
+	}
+	sort.Strings(ret)
+	return ret
+}
+func (timerlist *TimerList) GetTagValuesForKey(key string) []string {
+	var ret []string
+	added := make(map[string]bool)
+	for _, tmr := range timerlist.timers {
+		if v, ok := tmr.AdditionalTags[key]; ok && !added[v] {
+			ret = append(ret, v)
+			added[v] = true
+		}
+	}
+	sort.Strings(ret)
+	return ret
+}
+
 func (timerlist *TimerList) GetActiveTimers() *TimerList {
 	t := *NewTimerList()
-	for _, v := range *timerlist {
+	for _, v := range timerlist.timers {
 		if v.FinishDate.IsZero() {
-			t = append(t, v)
+			t.timers = append(t.timers, v)
 		}
 	}
 	return &t
@@ -88,7 +153,7 @@ func (timerlist *TimerList) GetActiveTimers() *TimerList {
 // String returns a complete list of timers in timer.txt format.
 func (timerlist *TimerList) String() string {
 	var ret string
-	for _, timer := range *timerlist {
+	for _, timer := range timerlist.timers {
 		ret += fmt.Sprintf("%s\n", timer.String())
 	}
 	return ret
@@ -96,24 +161,23 @@ func (timerlist *TimerList) String() string {
 
 // AddTimer prepends a Timer to the current TimerList and takes care to set the Timer.Id correctly
 func (timerlist *TimerList) AddTimer(timer *Timer) {
-	// The new timer is going to be id 1
-	timer.Id = 1
-	for _, t := range *timerlist {
-		// Everything else gets incremented
-		t.Id++
-	}
-	// Now prepend the timer to the slice
-	*timerlist = append(*timerlist, &Timer{})
-	copy((*timerlist)[1:], (*timerlist)[0:])
-	(*timerlist)[0] = timer
+	timerlist.timers = append(timerlist.timers, timer)
+	timerlist.refresh()
 }
 
+// AddTimers adds all passed in timers to the list, sorts the list, then updates the Timer.Id values.
+func (timerlist *TimerList) AddTimers(timers []*Timer) {
+	timerlist.timers = append(timerlist.timers, timers...)
+	timerlist.Sort(SORT_START_DATE_ASC)
+}
+func (timerlist *TimerList) Combine(other *TimerList) { timerlist.AddTimers(other.timers) }
+
 // GetTimer returns the Timer with the given timer 'id' from the TimerList.
 // Returns an error if Timer could not be found.
 func (timerlist *TimerList) GetTimer(id int) (*Timer, error) {
-	for i := range *timerlist {
-		if ([]*Timer(*timerlist))[i].Id == id {
-			return ([]*Timer(*timerlist))[i], nil
+	for i := range timerlist.timers {
+		if timerlist.timers[i].Id == id {
+			return timerlist.timers[i], nil
 		}
 	}
 	return nil, errors.New("timer not found")
@@ -122,38 +186,40 @@ func (timerlist *TimerList) GetTimer(id int) (*Timer, error) {
 // RemoveTimerById removes any Timer with given Timer 'id' from the TimerList.
 // Returns an error if no Timer was removed.
 func (timerlist *TimerList) RemoveTimerById(id int) error {
-	var newList TimerList
 	found := false
-	for _, t := range *timerlist {
-		if t.Id != id {
-			newList = append(newList, t)
-		} else {
+	var remIdx int
+	var t *Timer
+	for remIdx, t = range timerlist.timers {
+		if t.Id == id {
 			found = true
+			break
 		}
 	}
 	if !found {
 		return errors.New("timer not found")
 	}
-	*timerlist = newList
+	timerlist.timers = append(timerlist.timers[:remIdx], timerlist.timers[remIdx+1:]...)
+	timerlist.refresh()
 	return nil
 }
 
 // RemoveTimer removes any Timer from the TimerList with the same String representation as the given Timer.
 // Returns an error if no Timer was removed.
 func (timerlist *TimerList) RemoveTimer(timer Timer) error {
-	var newList TimerList
 	found := false
-	for _, t := range *timerlist {
-		if t.String() != timer.String() {
-			newList = append(newList, t)
-		} else {
+	var remIdx int
+	var t *Timer
+	for remIdx, t = range timerlist.timers {
+		if t.String() == timer.String() {
 			found = true
+			break
 		}
 	}
 	if !found {
 		return errors.New("timer not found")
 	}
-	*timerlist = newList
+	timerlist.timers = append(timerlist.timers[:remIdx], timerlist.timers[remIdx+1:]...)
+	timerlist.refresh()
 	return nil
 }
 
@@ -177,9 +243,9 @@ func (timerlist *TimerList) ArchiveTimerToFile(timer Timer, filename string) err
 // bool), and returns a new TimerList. The original TimerList is not modified.
 func (timerlist *TimerList) Filter(predicate func(*Timer) bool) *TimerList {
 	var newList TimerList
-	for _, t := range *timerlist {
+	for _, t := range timerlist.timers {
 		if predicate(t) {
-			newList = append(newList, t)
+			newList.timers = append(newList.timers, t)
 		}
 	}
 	return &newList
@@ -188,7 +254,7 @@ func (timerlist *TimerList) Filter(predicate func(*Timer) bool) *TimerList {
 // LoadFromFile loads a TimerList from *os.File.
 // Note: This will clear the current TimerList and overwrite it's contents with whatever is in *os.File.
 func (timerlist *TimerList) LoadFromFile(file *os.File) error {
-	*timerlist = []*Timer{} // Empty timerlist
+	timerlist.timers = []*Timer{} // Empty timerlist
 	timerId := 1
 	scanner := bufio.NewScanner(file)
 	for scanner.Scan() {
@@ -202,12 +268,13 @@ func (timerlist *TimerList) LoadFromFile(file *os.File) error {
 			return err
 		}
 		timer.Id = timerId
-		*timerlist = append(*timerlist, timer)
 		timerId++
+		timerlist.timers = append(timerlist.timers, timer)
 	}
 	if err := scanner.Err(); err != nil {
 		return err
 	}
+	timerlist.refresh()
 	return nil
 }
 
@@ -235,12 +302,12 @@ func (timerlist *TimerList) WriteToFilename(filename string) error {
 }
 
 // LoadFromFile loads and returns a TimerList from *os.File.
-func LoadFromFile(file *os.File) (TimerList, error) {
+func LoadFromFile(file *os.File) (*TimerList, error) {
 	timerlist := TimerList{}
 	if err := timerlist.LoadFromFile(file); err != nil {
 		return nil, err
 	}
-	return timerlist, nil
+	return &timerlist, nil
 }
 
 // WriteToFile writes a TimerList to *os.File.
@@ -249,12 +316,12 @@ func WriteToFile(timerlist *TimerList, file *os.File) error {
 }
 
 // LoadFromFilename loads and returns a TimerList from a file (most likely called "timer.txt")
-func LoadFromFilename(filename string) (TimerList, error) {
+func LoadFromFilename(filename string) (*TimerList, error) {
 	timerlist := TimerList{}
 	if err := timerlist.LoadFromFilename(filename); err != nil {
 		return nil, err
 	}
-	return timerlist, nil
+	return &timerlist, nil
 }
 
 // WriteToFilename write a TimerList to the specified file (most likely called "timer.txt")